The present invention relates to apparatus and methods for powering peripheral devices. More particularly, the present invention relates to improved techniques for powering and/or charging peripheral devices through a data transmission line.
FIG. 1 is an exemplary block diagram of an electronics system 10. The electronics system 10 includes a peripheral device 12 and a host device 14, both of which are capable of processing data. The electronics system 10 also includes a data transmission line 16 that operatively couples the peripheral device 12 to the host device 14. The data transmission line 16 allows data to be transmitted between the peripheral device 12 and the host device 14, i.e., data may be uploaded or downloaded between the devices. In most cases, the peripheral and host devices 12 and 14 include data ports 18 and 20 respectively, for receiving the data connectors of the transmission line 16.
The peripheral device 12, host device 14 and transmission line 16 may take many forms. For example, the peripheral device 12 may be a portable device such as a personal computer, personal digital assistant, cellular phone, digital camera, media player, and the like. The host device 14, which may be portable as well, may also be a general purpose computer such as a desktop computer. In addition, the transmission line 16 may be capable of transmitting data via a serial, parallel, PS/2, small computer system interface (SCSI), universal serial bus (USB), network, FIREWIRE port (IEEE 1394-1995), and the like. Although some of these transmission lines include lines for transmitting both data and power, it should be noted that the power flowing through the transmission lines is typically incidental power used in processing data. That is, the power is not used to supply power for normal operation of the devices, as for example powering up or charging batteries in the case of portable devices (e.g., power is not supplied through the data transmission line when operating with power from a battery of external power source).
In order to operate and/or charge the devices 12 and 14, the system typically includes dedicated power cables that connect the respective devices to an external power source. In this exemplary system 10, the peripheral device 12 is connected to an electrical outlet 22 through a dedicated power cable 24 that includes a plug 26 that receives AC current from the electrical outlet 22, a power adapter 28 that turns AC current into DC current, and a connector 30 that distributes the DC current through a power port 32 of the peripheral device 12. As is generally well known, DC current (3 to 12 volts and less than 1 amp of current) is required to operate most electronic devices and to recharge batteries that store DC current. Although not shown in FIG. 1, in some cases the power adapter and plug may be combined into a single unit.
While the system described above works well, it would be desirable to remove the total number of connections made to a peripheral device so as to reduce the number of connectors and cables needed to operate the peripheral device. By reducing the number of connectors and cables, the peripheral size and the cost of the product may be decreased as well as the ease of use of the peripheral device may be improved (less cables to tote around).